Dumb Question On Fuel Gravity Feed

[Jerry Hudgens]

Say you have two tanks connected at the bottom with a straight pipe coming out of the center of each tank and then the two tanks connected by a pipe between them at the bottom which is level.

If the two tanks are the exact same size and shape and are mounted at exactly the same height, and you pour gasoline in one tank to fill it to half way so that gas flows to the empty tank, when the gas flows out of the tank over to the other tank, when will the gas stop flowing?

Is it when the top of the gas in the tank that is getting the gas from the other tank reaches the same height as the top of the gas in the tank that you filled to halfway?

I know this is dumb but I have had a problem setting up my Jeep without mounting a gas tank in place and connecting a fuel pump.

Any thoughts?

Jerry Hudgens

[rjbeamer]

The tanks will equalize with the fuel level measured at the top of the liquid. In other words the the 2 tanks will have the top of the liquid at the same level.

Roger

[Chuck Lutz]

Correct me I am wrong but I think your real question is how to use a spare gas canister to provide fuel to the pump and bypass all the fuel lines, strainer and the under-seat tank. If that is the question, then as long as you route a flexible gas line from the spare tank and that tank is approximately as high or higher, the pump should have no problem pulling fuel to it and on to the carb. You will be bypassing the existing plumbing and connecting that flexible temporary gas line to the IN side of the fuel pump. Be sure to let AIR into the spare tank to replace the gas you are pumping out of it!

[tamnalan]

I agree with Roger. If the two tanks are connected at their low points so that fuel can migrate freely and if both tanks are vented so that atmospheric pressure acts equally on both, then the final fuel levels should be the same.

If the two tanks are identical and mounted at the same elevation, then the fuel quantities in both should remain approximately the same as fuel is withdrawn from the connected low point.

My $0.02

[Jerry Hudgens]

Thanks guys for the responses.

I thought that what you posted was correct but I was not completely sure. I am getting old and my thought processes are not always correct.

You are right in that I do not want to mount my new gas tank (bought many years ago) and plumb it up until I get some work done on the body. I just want to hook up a small tank with gravity feed so that I can crank the Jeep and drive it in and out of my garage.

Again, thanks

Jerry Hudgens

[tamnalan]

In my humble opinion Jerry, the only dumb question is the one that remains unasked. I enjoy your posts and often learn something from them. Ask away!

[Warwick]

The tanks will equalize with the fuel level measured at the top of the liquid. In other words the the 2 tanks will have the top of the liquid at the same level.

Roger

This useful principle is employed in the 'water level' device sometimes used in surveying. See https://en.wikipedia.org/wiki/Water_level_(device)

Warwick